Electrical connectors are often fabricated using a plurality of independent pins held in a spaced-apart fashion by a nonconductive support member. The portion of the pins which make contact with a female connector are preferably plated with a thin layer of gold or other precious metal which exhibits the properties of excellent conductivity while, at the same time, evidencing good corrosion resistance. The opposite ends of the connector pins are generally plated with a lead/tin coating to enable a good solder connection to be achieved when conductors are connected thereto and the assembly heated. Thus, the optimum connector pin is selectively plated, at one end, with a precious metal which provides good electrical contact and corrosion resistance, while at the other end, with a lead/tin material for solderability purposes. It is not desirable to plate the entire pin with the precious metal as that adds considerably to the expense. Various connector pin plating systems are known in the prior art. In U.S. Pat. No. 4,321,124 to Audelo a selective loose parts plating apparatus is shown wherein the parts are carried in apertures in a continuous belt. The portion of each part that is desired to be selectively plated is moved by the belt through a plating solution so that only that portion which extends into the solution is plated. Similar systems are shown in U.S. Pat. No. 4,279,730 to Noz, U.S. Pat. No. 4,545,884 to Francis and U.S. Pat. No. 3,657,097 to Baldock et al. In each of the aforementioned patents, consideration is only given to plating one side of a connector pin, with little apparent attention given to the nonplated end.
In other prior art, it is known to reorient connector pins so that their nonplated ends may be selectively electroplated with another material. In such instances, the pins are often removed from the conveyor belt, reoriented and moved to another conveyor belt for the second plating operation. This requires separate plating lines, significant handling of the pins, allocation of substantial manufacturing space to the second plating line and generally results in an increased cost for the product.
Accordingly, it is an object of this invention to provide an improved selective plating system for connector pins, which system occupies minimum manufacturing floor space.
It is another object of this invention to provide an improved selective plating system for connector pins wherein pin handling is minimized.
It is still another object of this invention to minimize the amount of precious metal which must be used in a selective electroplating apparatus for connector pins.